Novel NaClO4 and NaPF6 Based Non-Aqueous Electrolytes for Electrical Double Layer Capacitor Application
Ann Laheäär, Alar Jänes, Enn Lust · ECS Transactions · 2013
Novel non-aqueous electrolytes – 1 M NaClO4 and 1 M NaPF6 solutions in ethylene carbonate/dimethyl carbonate solvent mixture – were studied for the application in electrical double layer capacitors (EDLCs) with carbide-derived carbon electrodes. Electrochemical characteristics – region of ideal polarizability, values of series capacitance, high-frequency resistance, time constants, etc. were analysed by applying cyclic voltammetry, impedance spectroscopy and constant current charge/discharge methods both in two- and three-electrode test cells. Based on calculated specific energy and power values and other data obtained, Na-salts based EDLC test cells have similar electrochemical behavior compared to LiPF6 and LiClO4 based systems (studied earlier). Na intercalation/chemical bounding to electrode surface was verified by XPS analysis. Despite the moderate cycle life of Na-salts based EDLCs, these electrolytes are an interesting option for high power/energy devices.